Collector ring



April 23, 1940. a SPEAR 2,198,395

COLLECTOR RING Filed July 18, 1958 Patented Apr. 23, 1940 UNITED STATESPATENT OFFICE 5 Claims.

My invention relates to new and useful improvements in collector ringsfor electrical machines; such as generators, motors, rotary converters,or other types of alternating current machines in which a rubbingcontact is maintained between the brushes and the ring contacts mountedon a rotary element.

Heretofore, as rings have been ordinarily constructed, it was extremelydiflicult to replace the old worn ring with a new one. The collectorring according to my invention is constructed with a removable wearingmember so that when the wearing surface of the ring is worn, this membermay be replaced easily and readily. I divide my collector ring into twoparts which for convenience are termed respectively, the inner ringmember and the outer or wearing ring member.

The primary object of my invention is to provide a form of collectingdevice, such that the parts thereof are easily constructed and readilyassembled and such that the outer wearing member is firmly andeffectively connected mechanically to the inner ring member by means ofscrewthreads and a screw set.

A further object of my invention is to substan- A tially increase thesurfaces of the two members in contact so that there shall be themaximum electrical conductivity and no resistance developed betweenthem. 1

Another object of my invention is to construct a simple and eflieientform of a collector ring which can be changed readily without removingthe rotor of the dynamo-electric machine but which will not work looseunder the stress of operating conditions.

With the foregoing and other objects in view which will appear as thedescription proceeds, my invention consists in the novel featureshereinafter described in detail, illustrated in the accompanyingdrawing, and particularly pointed out in the appended claims. It will beunderstood that the invention is not limited to the details disclosedbut includes all such variations and modifications as fall within thespirit of my invention and the scope of the appended claims.

In the drawing:

Fig. 1 is a side view partly in section showing the shaft, the inner andouter ring members, with the latter secured according to my invention;

Fig. 2 is a side elevation of the collector ring mounted on the rotorshaft, and

Fig. 3 is a transverse section along line 3--3 of Fig. 2.

As shown in detail in the drawing, the improved collector ring includesa rotor shaft 4, an

inner ring member 5 and an outer member 6. The inner member of thecollector ring is insulated from shaft 4, the insulation being shownat 1. I provide a key 8 by which the inner ring member is keyed to theshaft.

The inner and outer ring members are firmly secured together by means ofa screw thread 9, preferably relatively fine such as thirty-six threadsper inch for a motor of average size. In

order to secure more firmly the two ring members, 7

I use a set screw Ill which may be of twelve gauge and twenty-fourthreads per inch for such a motor. I next provide two holes II in oneside wall of the outer member for a spanner wrench in order tofacilitate its assembly on the inner memher or its removal forreplacement.

At the left of Fig. l, I have iullustrated the complete assembly partlyin cross-section. The assembly is shown in side elevation in the centerand at the right is shown the inner ring alone. The connections betweenthe inner rings and the individual windings of the rotor or armature areof the usual construction and have been omitted for simplicity inillustration.

My arrangement permits permanent mounting of the inner rings on theshaft and their connection with the armature windings. The diameters ofthe several inner rings may be progressively diminished in the directionaway from the armature windings to allow easy clearance in assembly andremoval of the separate outer rings.

These outer rings are assembled on the respective inner rings byscrew-threading. The fineness of the threads increases materially thecontact surfaces between each outer wearing member and the inner member.Thus the electrical conductivity between each pair of rings is notmaterially affected by this mode of assembly. The screw-threading isfacilitated by the use of a spanner wrench in the holes I I.

The final attachment between the inner and outer rings consists of theset-screw i0. This locks the rings against relative rotation. At thesame time it permits slight thermal expansion of the outer ring relativeto the inner ring. Such expansion does not lessen materially theelectrical conduction between the rings since adequate contacting areais providedby the fineness of the screw-threads. When the wearingsurface of the outer ring becomes Worn, pitted or uneven, the ring maybe removed for repair or replacement in the manner above described.

This structural arrangement is a suitable means whereby the inner andouter ring members may be effectively secured and the invention mayobviously be varied within the scope of the appended claims.

What I claim is:

1. A collector ring comprising an inner ring member and an outer ringmember, the inner member having a threaded outer annular surface, andthe outer member having a threaded inner annular surface directlyengaged with said outer surface.

2. A collector ring comprising an inner ring member and an outer ringmember, the outer member being secured to the inner member by threadedmeans and by a set screw in co-operation with said threaded means.

3. A current-collecting device for electrical machines, a supportingmember, an inner ring member fixed to said supporting member, and anouter ring member secured to the inner ring member by means of screwthreads.

4. A collector ring comprising an inner ring member screw-threaded onits outer surface, an outer ring member internally screw-threaded, andmeans for locking said members together against relative rotation.

5. In combination a collector ring comprising an armature shaft with akey-Way, an inner ring member screw-threaded on its outer surface,insulation between said shaft and ring, a key for fastening the ring onthe shaft, an outer Wearing ring having internal screw-threadscomplementary to those on the inner ring, and means for locking therings together.

HARRY B. SPEAR.

